Good morning!
This is what
we do....
We put Harry's Choke Free harness on, and then put him in his crate which is sideways-on. We then attach a lead-like thing to his harness, which we thread through the crate, and it slots into a seat-belt slot.
We then put the shoulder strap all the way round the crate, and slot it into the other seat-belt slot. Does that make sense?!!?

Sally + Harry x